铈盐对铝合金的缓蚀机理研究

应用分离电解池(the split cell)技术将阴阳极分离,通过测定因溶液中氧含量改变和添加CeCl3导致两电极之间的净电流的变化,研究了CeCl3对B95超强铝合金在0.1 mol/L NaCl溶液中腐蚀行为的影响,并用扫描电子显微镜(SEM)和X射线能量散射谱(EDS)表征电极表面的形貌特征,结合其它电化学技术如电位-时间曲线、极化曲线等手段,对Ce盐缓蚀机理作了深入探讨.结果表明,经Ce盐处理的B95超强铝合金表面可形成一层不均匀分布的转化膜,成膜动力学包括铝合金的溶解及随后的成膜两个过程;铝合金Ce化学转化膜主要由Ce、O、Al组成;3.5%NaCl溶液全浸试验表明添加CeCl3后腐蚀率可降低数百倍,铝合金的耐蚀性能大大提高,CeCl3表现为一种优良的铝合金缓蚀成膜剂.

CORROSION INHIBITION MECHANISM OF CERIUM(Ⅲ) FOR ALUMINUM ALLOY

By using a split cell to separate anode and cathode as well as measuring the change of net-electric current between the two electrodes caused by the change of the amount of oxygen in the solution and the addition of CeCl_3.The influence of CeCl_3 on corrosion behavior of B95 super-strength aluminum alloy in the 0.1 mol/L NaCl solution was studied.Meanwhile,a further discussion about Ce salt inhibition mechanism was carried out by revealing the features of electrode surface with the help of SEM and X-ray energy-dispersive spectrometry(EDS) and resorting to other electric chemical techniques,such as potential-time curve,polarization curve and so on.The results showed that a layer of uneven conversion coatings could appear on the surface of B95 alloy after being dealt with by Ce salt;the dynamics of coating-formation involved two stages:the solution of aluminum alloys and coating-formation afterwards;the cerium conversion coatings were mainly composed of Ce,O and Al elements;the experiment with completely submerging into the solution of 3.5% NaCl showed that the corrosion rate of B95 could be reduced by several hundred times and the anti-corrosion performance of aluminum alloys improved greatly when CeCl_3 were added to the solution.As a result CeCl_3 proves to be an excellent coating-formation material and aluminum alloy corrosion inhibitor.